Newly Discovered Fossils Suggest Ancient Age of Monotremes in Australia
Bones encased in rock rotted away, and water-borne silica seeped into the crevices, solidifying into opal and preserving precious details for 100 million years. The resulting fossils now provide evidence that there may have been an Age of Monotremes before other mammals came to dominate.
"It's like discovering a whole new civilization," says Australian Museum paleontologist Tim Flannery. "Today, Australia is known as a land of marsupials, but discovering these new fossils is the first indication that Australia was previously home to a diversity of monotremes."
Currently, only five species of these rare mammals exist: one platypus and four echidna species, shared between Australia and Papua New Guinea. Due to their reptilian-like egg-laying feature, it has long been thought that these...